The general tectonics of complex impact crater formations, as well as the impact crater mechanics, have been considered in detail by many researchers (e.g., Grieve 1987, Melosh 1989, Melosh and Ivanov 1999, Kenkmann 2002, and others). On the contrary, the post-early modification stage tectonic history of impact structures is neglected, because of the most of them are essentially modified by erosion or buried beneath later sediments. In this paper, we present data on post-impact faulting within a well-studied large impact crater - the about 35-Ma old Popigai structure. The objective is to show real features of post-consolidation brittle deformations within impact rock sequences, obtained

Fig. 2. Post-impact tectonic structure of the Popigai crater. Fault blocks differing in extent and direction of post-impact vertical displacements are distinguished.

from detailed geological mapping combined with aerial photo interpretation, and thereby to draw attention to the problem of the late modification stage evolution of impact structures. In this aspect, Popigai is one of the best objects due to its good preservation and exposure, and detailed investigations that were made through deep drilling and from abundant outcrops of diverse impact lithologies.

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